Fix emails being sent with the wrong mail address, fix #713

All emails have to be sent with the email configured in the Site. Spams
and feedbacks were being sent with the email of the user that created the
spam/feedback. This fails for some SMTP servers and is wrong.
fixes #679 The welcome message shouldnt link the BigBlueButton videos, but the SE-Mconf documentation
Add .ruby-version
Merge branch 'master' into recordings
Merge remote-tracking branch 'origin/bug679' into recordings